Conventional rowing exercise devices, which utilize a flywheel as a resistance source, are mechanically simple, whereby the rotational inertia of the flywheel provides a good replication of the resistance experienced during actual rowing. Nevertheless, in the prior art devices the mechanically simple devices are still more complex than they need to be.
FIGS. 1 and 2 illustrate a conventional flywheel-type rowing exercise device with a chain take-up and handle return, in which a stationary base 2, with ground engaging legs and feet, supports a flywheel 1 rotatably mounted at one end, and a seat 3, which is slideable on the base 2 from an end opposite the flywheel 1 to a position midway between the two ends. A shaft 4, to which is fixed a sprocket or pulley 5, is rotatably and transversely mounted on a raised front portion of the base 2 on which the flywheel 1 is mounted, and freely rotates in one direction. The seat 3 is free to slide or roll fore and aft on a seat rail 6 mounted longitudinally on the frame 2.
The user sits on the seat 3, places their feet on footrests 7 and grasps a handle 8. The handle 8 is connected to a rope 9, which passes around sprocket or pulley 5 and then is routed around and between a multiplicity of pulleys or sprockets 13, around moveable pulley assembly 11, and fixed to fixed pulley assembly 11. The moveable pulley assembly 11 is connected to an elastic cord or spring 12, which is routed around and between pulleys 13 and fixed at both ends to the base 2.
Pulling on the handle 8 pulls the rope 9 around sprocket or pulley 5, which causes the flywheel 1 to rotate and the moveable pulley assembly 11 to move towards the fixed pulley assembly 10. This in turn causes elastic cord 12 to elongate under tension, which is accommodated by the rotation of pulleys 13. Upon return of the handle 8, a uni-directional clutch in the hub of the flywheel 1 disengages, allowing the flywheel 1 to continue to rotate. The slack of the chain 9 is taken up by the return of the moveable pulley 11 to its rest position through the force of contracting the elastic cord 12.
Variations of this chain delivery and take-up means have been utilized in a multitude of prior art flywheel-type rowing exercise devices, such as the ones disclose in U.S. Pat. No. 4,396,188 entitled “Stationary Rowing Unit”, issued in 1983 to Dreissigacker; U.S. Pat. No. 5,382,210, entitled “Dynamically Balanced Rowing Simulator”, issued in 1995 to Rekers; U.S. Pat. No. 5,779,600, entitled “Rowing Simulator”, issued in 1998 to Pape; U.S. patent application Ser. No. 12/796,357, entitled “Dynamic Rowing Machine”, filed by Roach; and U.S. Pat. No. 7,862,484, entitled “Folding Exercise Rowing Machine”, issued in 2011 to Coffey.
Unfortunately, for all of these prior art devices, repeated elongation of the elastic cord, e.g. 12, used to provide a biasing force on the chain, eventually results in a loss of elasticity of the cord, and subsequent loss of the force required to briskly take up the chain during the return (recovery) portion of the stroke. Typically, these exercise devices provide a means to adjust the tension of the spring or elastic cord when this occurs, but eventually the elastic element must be replaced.
Additionally, the elasticity of an elastic cord is affected by temperature. An exercise device which incorporates an elastic cord does not function properly in an unheated area in a cold climate. The elasticity of the cord decreases with a decrease in ambient air temperature, resulting in a sluggish chain take-up and a too slow handle return.
Also, differences in elasticity and tension of the elastic cord from one device to another results in differences of force required to move the handle. User competitions on flywheel-type rowing exercise devices have become popular, with worldwide age rankings and records. It could reasonably be argued that all such competition results and records are invalid because of the possibility of tension differences of the elastic element from one device to another. A competitor using a device with an elastic cord adjusted to a lower tension than the devices of the other competitors (but still sufficient to return the handle briskly) will have an indisputable advantage.
Finally, the prior art labyrinthine configurations of chain and elastic cord, and the multitude of pulleys, sprockets, bearings, brackets, and shafts required in these assemblies, are at odds with the essentially simple concept of a flywheel-type rowing exercise device, i.e. pull on a handle, spin a flywheel, return the handle, repeat.
U.S. Pat. No. 4,772,013 issued in 1988 to Tarlow, attempts to eliminate the elastic element in the chain take-up and handle return means by the use of a continuous chain and cable loop that passes around the flywheel sprocket and around and between fixed pulleys and sprockets positioned fore and aft on the device. The handle is secured in the middle of the exposed upper horizontal section of the chain/cable loop. However, the disclosed and functionally necessary three point chain/cable connection to the handle would seem to limit the handle design to a monolithic, rigid structure. Thus it would be unworkable, or at best awkward, to attempt to combine the Tarlow chain take-up and delivery system with the “Articulated Handles for Rowing Exercise Devices”, U.S. Pat. No. 8,038,582 issued in 2011 to Edmondson.
An object of the present invention is to overcome the shortcomings of the prior art by providing a simpler pulley return system using the force of gravity instead of an elastic cord.